The generator shaft grounding carbon brush has two main functions:
The first is to eliminate electrostatic charges.
The second is to provide a grounding point for rotor grounding protection. In normal operation, the rotor being well insulated from the ground, the rotor earthing protection device has only one "earthing point" (provided by the earthing carbon brush of the large tree) and the protection does not work. When the insulation of the motor rotor from the ground decreases (when one-point grounding occurs), for the protection of the rotor grounding, "two-point grounding" is formed using the “grounding point” of the large tree grounding. carbon brush. If the balance of the bridge constituting the path or bridge principle is destroyed or the measured impedance of the ping-pong principle changes, a proteThe grounding action of the point will operate and an alarm signal will be issued.